Plastic ski

ABSTRACT

A plastic ski having a core formed generally in the shape of a ski and upper and lower cover layers on opposite sides of the core. A surface liner is positioned on the upper cover layer and a sole liner on the lower cover layer. Metallic edge members are placed along the edge of the ski between the layers and liners. The core, layers, liners and edges may be appropriately provided with corresponding ridges and recesses for interlocking the members together and forming a composite cross section having closed surfaces on all sides. With the possible exception of the edge members, the various elements are made of plastic material.

United States Patent [1 1 Benner [451 Apr. 2, 1974 PLASTIC SKI [76] Inventor: Wolfgang Benner,

Landsiedlerstrasse, 7184 Kirchberg, Jagst, Germany [30] Foreign Application Priority Data June 4, 1970 Germany 2027370 [52] US. Cl. 2811/1113 L [51] Int. Cl. A63c 5/12 [58] Field of Search280/l1.13 L, 11.13 E, 11.13 R,

359,598 5/1938 Italy 280/1 1.13 L 1,382,829 11/1964 France 280/1 1.13 L 1,428,988 1/1969 Germany l 280/1 1.13 N 2,005,056 12/1969 France 280/1 1.13 L

Primary Examiner-David Schonberg Assistant ExaminerMi1ton L. Smith Attorney, Agent, or Firm-Arthur Schwartz [57] ABSTRACT A plastic ski having a core formed generally in the shape of a ski and upper and lower cover layers on opposite sides of the core. A surface liner is positioned on the upper cover layer and a sole liner on the lower cover layer. Metallic edge members are placed along the edge of the ski between the layers and liners. The core, layers, liners and edges may be appropriately provided with corresponding ridges and recesses for interlocking the members together and forming a composite cross section having closed surfaces on all sides. With the possible exception of the edge members, the various elements are made of plastic mate rial.

17 Claims, 8 Drawing Figures PLASTIC SKI BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to laminated ski constructions, and in particular to composite ski constructions including interlocking profiles of plastic material.

2. Description of the Prior Art In the conventional fabrication of skis, the starting element is a wooden core which tapers toward the scoop as well as toward the rear end of the ski. To the core is joined upper and lower cover bands which are cut from two blocks of wood and glued together. Between these layers may be arranged, if desired, layers of glass fiber reinforced plastic. To this combination is then glued a plastic surface layer as well as a plastic sole liner. The assembly is then compressed in a heated die. Subsequently, the lateral edges and the point of the raw ski are molded to the desired contour, and the machine surfaces are covered with a lateral liner, such as, for example, a layer of epoxy resin. In a further operation, grooves must be added in the sole liner and, as the case may be, also in the upper cover liner in order to accommodate the protective metal edges.

It has also been suggested to fabricate the so-called core wedge from a hard foam plastic in order to eliminate the time necessary for the aging and storage of the wood and to save the operations of gluing, pressing, and contour milling required for the wooden wedges produced by gluing together several blocks of wood. An additional advantage of this method is the reduction in the weight of the ski. This improved fabrication method nevertheless requires additional work operations similar to those mentioned earlier with respect to the upper and lower wooden cover liners. In addition, the hard foam core and the other glued and pressed layers must be contour milled and the natural edges covered. Furthermore, as even the most unsophisticated version of skis normally includes steel edges, the mounting of these edges requires milling and screwing operations which are time consuming and therefore costly.

SUMMARY OF THE INVENTION It is an object of the invention to provide a composite ski construction, the fabrication of which requires a minimum of time consuming and costly successive operations. The end product is thereby less expensive, while maintaining and even improving its durability and skiing characteristics over a comparable ski produced in accordance with conventional methods.

In order to attain this objective, the invention provides a composite ski structure including an injection molded core formed in accordance with the ski contour, together with correspondingly molded upper and lower cover layers. Also, surface and sole liners are provided with matching and interlocking longitudinal grooves and ridges, with or without longitudinal interruptions. The various elements are glued together so as to produce a ski structure having a full overall profile which is closed on all sides. The core and the two cover layers are thereby preferably injection molded in hard foam plastic to the ski contour. These elements have a zone of material having a greater density on its entire periphery so as to give it a resilient cross section.

The invention, by substituting hard foam plastic parts which can be injection molded in great numbers for the previously used load carrying structural elements made of laminated wood, eliminates the need for storing and aging the wooden spars. Also eliminated is the machining and gluing to blocks, as well as the cutting of these laminated blocks to form core elements and cover layers. Additional savings in production time and production machinery are realized by the elimination of the lateral contour milling which is unnecessary with injection molded hard foam elements. It is also unnecessary to provide the additional operation of laterally covering the machined wood section with a plastic liner or a layer of epoxy resin. Because the density of the hard foam plastic is controllable and adjustable, the ski structure provided by the invention can be made comparatively light in weight, while maintaining an adequate stress resistance which is assured by the peripheral zones of higher density in the manner of a monocoque construction. This dense and essentially porefree peripheral zone of the hard foam plastic elements makes any additional lateral liners unnecessary. The matching and interlocking longitudinal grooves and longitudinal ridges'provided in the profile of the hard form elements and, as the case may be, in the profiles of the surface and sole liners, make it possible to rapidly (and, if desired, mechanically) assemble the elements without any lateral shifting during assembly. The surface and sole liners, which normally are of plastic material, may be preformed in a manner similar to that of the hard foam parts. Alternatively, they may be glued and pressed to the structural core and then contoured or cut by a suitable plastic machining method. However, this last operation may also be performed in a cost-saving manner by contouring a whole stack of liners before they are glued to their cores.

A further feature of the invention includes the provision of longitudinal grooves in the core as well as in the upper and lower cover layers. These elements are then laterally fixed against one another during assembly by inserting key profiles in the grooves. These key profiles may be of wood, plastic, or glass fiber reinforced plastic.

In one particular embodiment of the invention, the upper cover layer is provided with marginal recesses for the accommodation of corresponding lower ridges provided on the surface liner. The lower cover layer has similar marginal recesses for the accommodation of steel edges of an angular profile, the horizontal web portion of which creates a flush lower surface plane with the lower cover layer for the application of the sole liner.

In a preferred embodiment of the invention, the upper and lower cover layers represent stiffening layers of glass fiber reinforced plastic of equal or variable width. These stifiening layers extend over the entire length of the ski, and at one end they may have a contour to conform to the ski point. To position the stiffening layers relative to the hard foam core, the latter has on its upper and lower sides a recess as wide as the stiffening strip. Therefore, the assembly is again greatly simplified.

When the upper cover layer represents one of the above mentioned stiffening layers, it can be positioned relative to the core and the surface liner by providing sufficiently large recesses in the latter elements, all of them being glued together. Another solution includes the provision of the upper and lower cover layers stiffening layers) in large recesses in the core so as to form a flush surface with the horizontal web portions of the upper and lower metal edges whose angle profile engages a marginal recess in the core. The combination provides a positioning and gluing surface for the surface liner and the sole liner.

As a further refinement of the invention, the angle profile of the upper and lower metallic edges includes an additional longitudinal ridge oriented toward the center of the ski profile. The ridge extends from the horizontal web portion of the edge profile so as to form a Z-shape. These additional ridges may be obtained by either bending portions of the horizontal web profile, or by adding to the web profile an additional longitudinal ridge which is interrupted at several points so as not to diminish the elasticity of the ski. The angled portions or ridges serve as anchoring means in the core element or in the hard foam cover layers. Corresponding longitudinal grooves are provided in these parts, and the grooves are filled with glue for assembly. The Z-shaped profile is particularly advantageous when the lower and upper edges are of different widths so that the profile portions which reach toward the center of the composite structure are laterally offset while facing one another, thereby minimizing any weakening of the hard foam elements in thin portions of the composite ski structure.

BRIEF DESCRIPTION OF THE DRAWING In the accompanying drawing is illustrated schematically by way of examples several embodiments of the invention, represented in the various figures wherein:

FIG. 1 shows in cross section a composite ski profile embodying the invention, the individual elements of the profile being shown in an exploded view In underneath the assembled structure;

FIG. lb shows several partially modified elements of the embodiment of FIG. 1;

FIG. 2 and 2a shows a second embodiment of the invention in a representation similar to that of FIG. 1;

FIG. 3 and 3a shows another preferred embodiment of the invention including its separate elements; and

FIG. 4 shows a composite cross section similar to that of FIG. 3 at a thinner portion of the ski profile.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows in cross section an embodiment of the invention which has approximately the same number of structural elements as are used in conventional composite ski constructions. In contrast to the latter, however, a core element 10, an upper cover layer 11, and a lower cover layer 12 are made of injection molded hard foam plastic. The peripheral zones of these profiles have a dense structure in the form of a closed skin. Particularly suitable materials for this purpose are polyurethane, andpolystyrene, with a swelling agent to control the porosity added to the compound before introduction into the mold. The density of the peripheral zones can be controlled by regulation of the temperature of the injection mold, as well as by regulation of the inner pressure applied to it. These hard foam elements may include chopped glass fiber material in a homogeneous distribution, and are produced in their final shape and require no machining after injection molding. In order to simplify the assembly, the core element has a longitudinal ridge 13 on its upper and lower side, and the cover layers 11 and 12 are provided with matching grooves 14. The upper cover layer 1 1 also has a pair of longitudinal recesses 15 on its upper margin. These recesses receive matching marginal ridges 16 of a plastic surface liner 17. The lower cover layer 12 likewise has a pair of longitudinal recesses 18 in its lower margin for the accommodation of steel edge profiles 19. In the embodiment shown, these steel edges 19 have an angle profile which includes an upwardly oriented anchoring lip 20 which reaches into a pair of matching longitudinal grooves 21 in the recesses 18 of the cover layer 12. The groove 21 is filled with glue during assembly. In principle, it would also be possible to coat the steel edges 19 with a suitable adhesive layer, e.g. of resin or rubber, and to combine them with the cover layer in the injection molding process. The horizontal web portions of the edge profiles 19 are arranged flush with the lower side of the cover layer 12, thus permitting the gluing of a sole liner 22 directly to the combined lower sides thereof. In assembly, the separate elements as shown in FIG. 1 are coated with glue, then stacked into position, and assembled in a single compression operation to produce a finished composite ski structure.

In FIG. 1a is shown a modification of the embodiment of FIG. 1, whereby a core element 10a is provided with a pair of longitudinal grooves 13a in the place of ridges. These grooves receive longitudinal key profiles 23 glued thereto. The protruding portions of these key profiles match the longitudinal groove 14 of the cover layers 11 and 12. The key profiles 23, as well as the grooves 13a, may be of different height and depth, respectively, on different length portions of the ski profile, the former being reduced in portions of thinner overall cross section.

A second embodiment shown in FIG. 2 has the cover layers 11 and 12 serving as stiffening layers and being made of glass fiber reinforced plastic. They are positioned relative to the core element 10 in a pair of large longitudinal recesses 24 and 25. The width of the stiffening layers may be either constant over the entire length of the ski or it may vary so as to maintain a constant distance from the lateral edges of the ski. The upper stiffening layer 11 protrudes from the upper recess 24 of the core element, thereby forming a key profile to position the surface liner 16 which is placed on top of it. In contrast to FIG. 1, the marginal portions 16 of the surface liner 17 are directly glued to the core element 10. The lower stiffening layer 12 is completely received within the longitudinal recess 25 of the core element 10, forming a flush surface with adjacent edge shoulders 26. The steel edges 19 are positioned in longitudinal recesses 18 and 21 of the core element 10 rather than in the lower cover layer 12 as suggested in FIG. 1. Here, too, it is possible to assemble the steel edges 19 with the core element during the injection molding operation.

The third embodiment shown in FIGS. 3 and 4 is basically similar to that shown in FIG. 2, except that it includes a pair of upper protective edges 27 of hard aluminum with a surface liner 28 positioned therebetween. The upper edges 27 are formed in a suitable 2" profile which includes a downwardly oriented ledge 29 to be received by a longitudinal groove 30 in the core element 10. In the longitudinal direction, the ledge 29 of the protective edge 27 consists of separate, known continuous protrusions or bent web portions which are anchored inside the groove 30 with the aid of glue or resin. The upper side of the horizontal web portion of the upper protective edges 27, together with adjacent shoulders 31 bordering recess 24 in the core element and the stiffening layer 1 I placed therein, form a flush, continuous supporting surface for the surface liner 28.

The lower portion of the core element is arranged in a similar manner. The Z profile of the steel edges 32 likewise has a lip or ledge 33 extending toward the center of the composite profile and is adapted to be anchored inside the longitudinal groove 34 of the core element. The stiffening layer 12 is received inside the recess 25, and together with adjacent shoulders 35 of the core element and the lower sides of the horizontal web portion of the steel edges 32, forms a similar flush continuous surface for the application of the sole liner 22.

In FIG. 4 is shown a longitudinal portion of thinner overall cross section. Because the Z profiles are of different widths, they do not interfere with one another. This makes it possible for the core element 10 to be approximately the same thickness between the opposing ledges of the upper edge and lower edge as it is between the stiffening layers in the middle of the profile.

While there has been described and illustrated specific embodiments of the invention, it will be clear that variations in the details of the embodiments specifically illustrated and described may be made without departing from the true spirit and scope of the invention as defined in the appended claims.

I claim:

1. A ski comprising:

a. a core member of hard foamed plastic material formed generally in the shape of a ski;

b. upper and lower cover layer members of hard foamed plastic material positioned on opposite sides of said core member;

c. said core member and said cover layer members being provided with corresponding interlocking surfaces;

d. a surface liner member positioned on said upper cover layer member, and a sole liner member positioned on said lower cover layer member;

e. edge members having anchoring lips extending from the horizontal plane into one of the other members and being positioned between one of said liner members and one of said other members and having a portion extending along the edge of said liner member;

whereby all of said members are interlocked to form a composite cross section having closed surfaces on all sides.

2. A ski as defined in claim 1 wherein at least some of said members are formed of injection molded plastic material.

3. A ski as defined in claim 1 including chopped fiber material in a homogeneous distribution therein.

4. A ski as defined in claim 1 wherein said core member is tapered.

5. A ski as defined in claim 1 wherein said edge members are metal.

6. A ski as defined in claim 1 wherein said core member and at least one of said layer members has longitudinal grooves therein and a longitudinal key member in said grooves for positioning said core members and layer member relative to one another.

7. A ski as defined in claim 6 wherein said key member is made of a material selected from a group consisting of wood, plastic material and glass fiber reinforced plastic.

8. A ski as defined in claim 1 wherein said upper cover layer member includes a pair of longitudinal recesses along the upper and lower peripheral surfaces thereof and projecting ridges in the lower surface of said surface liner member.

9. A ski as defined in claim 1 wherein said lower cover layer memer includes longitudinal recesses on the lower surface thereof, said edge members having a horizontal portion thereof flush on its lower side with said lower cover layer member forming a supporting surface for said sole liner member.

10. A ski as defined in claim 1 wherein said upper and lower cover layer members are formed as stiffening layers of glass fiber reinforced plastic material.

11. A ski as defined in claim 1 wherein said edge members are Z-shaped and said anchoring lips extend into recesses in said core member.

12. A ski as defined in claim 1 wherein said lips form an edge bent from a horizontal web thereof.

13. A ski as defined in claim 1 wherein said lips form a longitudinal ledge which is interrupted at several points.

14. A ski comprising:

a. a core member of hard foamed plastic material formed generally in the shape of a ski;

b. upper and lower cover layer members positioned on opposite sides of said core member, said layer members being formed of injection molded hard foam plastic material preformed in the shape of ski contour, the peripheral zone of said layer members having said foam material of a greater density than the interior zone of said layer member;

c. a surface liner member positioned on said upper cover layer member, and a sole liner member positioned on said lower cover layer member;

d. edge members having a portion along the edges of the ski and being positioned between one of said liner members and one of the other members; and

e. said core member and at least some of said other members being provided with corresponding ridges and recesses formed thereon whereby the members are interlocked to form a composite cross section having closed surfaces on all sides.

15. A ski comprising:

a. a core member of hard foamed plastic material formed generally in the shape of a ski;

b. upper and lower cover layer members positioned on opposite sides of said core member;

c. a surface liner member positioned on said upper cover layer member, and a sole liner member positioned on said lower cover layer member;

d. edge members having a portion along the edges of the ski and being positioned between one of said liner members and one of the other members; and

e. said core member and at least some of said-other members being provided with corresponding ridges and recesses formed thereon, said upper cover layer member is completely positioned in a recess in said core member forming a supporting surface for said surface liner member, whereby the members are interlocked to form a composite cross section having closed surfaces on all sides.

16. A ski as defined in claim wherein said upper and lower cover layer members are completely positioned in recesses in respective sides of said core member said edge members being positioned on both sides of said core member and having a horizontal portion thereof forming flush, continuous supporting and adhesion surfaces for said surface liner member and sole liner member.

17. A ski comprising:

a. a core member of hard foamed plastic material formed generally in the shape of a ski;

b. upper and lower cover layer members positioned on opposite sides of said core member;

c. a surface liner member positioned on said upper cover layer member, and a sole liner member positioned on said lower cover layer member;

d. edge members having anchoring lips and having a portion along the edges of the ski and being positioned on the upper and lower surfaces of said core member, the width of the upper edge members being different from the width of the lower edge members whereby their respective anchoring lips are offset relative to each other; and

e. said core member and at least some of said other members being provided with corresponding ridges and recesses formed thereon whereby the members are interlocked to form a composite cross section having closed surfaces on all sides. 

1. A ski comprising: a. a core member of hard foamed plastic material formed generally in the shape of a ski; b. upper and lower cover layer members of hard foamed plastic material positioned on opposite sides of said core member; c. said core member and said cover layer members being provided with corresponding interlocking surfaces; d. a surface liner member positioned on said upper cover layer member, and a sole liner member positioned on said lower cover layer member; e. edge members having anchoring lips extending from the horizontal plane into one of the other members and being positioned between one of said liner members and one of said other members and having a portion extending along the edge of said liner member; whereby all of said members are interlocked to form a composite cross section having closed surfaces on all sides.
 2. A ski as defined in claim 1 wherein at least some of said members are formed of injection molded plastic material.
 3. A ski as defined in claim 1 including chopped fiber material in a homogeneous distribution therein.
 4. A ski as defined in claim 1 wherein said core member is tapered.
 5. A ski as defined in claim 1 wherein said edge members are metal.
 6. A ski as defined in claim 1 wherein said core member and at least one of said layer members has longitudinal grooves therein and a longitudinal key member in said grooves for positioning said core members and layer member relative to one another.
 7. A ski as defined in claim 6 wherein said key member is made of a material selected from a group consisting of wood, plastic material and glass fiber reinforced plastic.
 8. A ski as defined in claim 1 wherein said upper cover layer member includes a pair of longitudinal recesses along the upper and lower peripheral surfaces thereof and projecting ridges in the lower surface of said surface liner member.
 9. A ski as defined in claim 1 wherein said lower cover layer memer includes longitudinal recesses on the lower surface thereof, said edge members having a horizontal portion thereof flush on its lower side with said lower cover layer member forming a supporting surface for said sole liner member.
 10. A ski as defined in claim 1 wherein said upper and lower cover layer members are formed as stiffening layers of glass fiber reinforced plastic material.
 11. A ski as defined in claim 1 wherein said edge members are Z-shaped and said anchoring lips extend into recesses in said core member.
 12. A ski as defined in claim 1 wherein said lips form an edge bent from a horizontal web thereof.
 13. A ski as defined in claim 1 wherein said lips form a longitudinal ledge which is interrupted at several points.
 14. A ski comprising: a. a core member of hard foamed plastic material formed generally in the shape of a ski; b. upper and lower cover layer members positioned on opposite sides of said core member, said layer members being formed of injection molded hard foam plastic material preformed in the shape of ski contour, the peripheral zone of said layer members having said foam material of a greater density than the interior zone of said layer member; c. a surface liner member positioned on said upper cover layer member, and a sole liner member positioned on said loweR cover layer member; d. edge members having a portion along the edges of the ski and being positioned between one of said liner members and one of the other members; and e. said core member and at least some of said other members being provided with corresponding ridges and recesses formed thereon whereby the members are interlocked to form a composite cross section having closed surfaces on all sides.
 15. A ski comprising: a. a core member of hard foamed plastic material formed generally in the shape of a ski; b. upper and lower cover layer members positioned on opposite sides of said core member; c. a surface liner member positioned on said upper cover layer member, and a sole liner member positioned on said lower cover layer member; d. edge members having a portion along the edges of the ski and being positioned between one of said liner members and one of the other members; and e. said core member and at least some of said other members being provided with corresponding ridges and recesses formed thereon, said upper cover layer member is completely positioned in a recess in said core member forming a supporting surface for said surface liner member, whereby the members are interlocked to form a composite cross section having closed surfaces on all sides.
 16. A ski as defined in claim 15 wherein said upper and lower cover layer members are completely positioned in recesses in respective sides of said core member said edge members being positioned on both sides of said core member and having a horizontal portion thereof forming flush, continuous supporting and adhesion surfaces for said surface liner member and sole liner member.
 17. A ski comprising: a. a core member of hard foamed plastic material formed generally in the shape of a ski; b. upper and lower cover layer members positioned on opposite sides of said core member; c. a surface liner member positioned on said upper cover layer member, and a sole liner member positioned on said lower cover layer member; d. edge members having anchoring lips and having a portion along the edges of the ski and being positioned on the upper and lower surfaces of said core member, the width of the upper edge members being different from the width of the lower edge members whereby their respective anchoring lips are offset relative to each other; and e. said core member and at least some of said other members being provided with corresponding ridges and recesses formed thereon whereby the members are interlocked to form a composite cross section having closed surfaces on all sides. 